Polyaminopyrrolidines in lubricating oils



United States Patent This invention pertains to lubricating oilcompositions containing metal-free detergents having acid-neutralizingcharacteristics.

Present day internal combustion engines operate at high speeds and highcompression ratios. When used in the so-called city stop-and-go driving,which includes the greater part of the driving conditions for a largepercentage of todays automobiles, the internal combustion engines do notreach the most efiicient operating temperature. Under city drivingconditions, large amounts of partial oxidation products are formed, andreach the crankcase of the engine by blowing past the piston rings. Mostof these partial oxidation products are oil-insoluble, tending to formdeposits on the various operating parts of the engine, such as thepistons, piston rings, etc. For the purpose of preventing the depositionof these products on the various engine parts, it is necessary toincorporate detergents in the lubricating oil compositions, thus keepingthese polymeric products highly dispersed in a condition unfavorable fordeposition on metals.

For the most part, the various detergents which are added to crankcaseoils to reduce this formation of sludges and varnishes are metal organiccompounds, particularly those compounds wherein the metal is linked toan organic group through an oxygen atom. Although these metal-containingorganic compounds have some efiectiveness as detergents for dispersingthe precursors of deposits within the oil itself rather than permittingthem to form added deposits on the engine parts, they have the disadvantage of forming ash deposits in the engine. These ash depositslower engine performance by fouling spark plugs and valves, andcontribute to preignition.

It is a particular object of this invention to provide lubricating oilcompositions which are compounded with metal-free detergents havingacid-neutralizing characteristics.

Therefore, in accordance with this invention, it has been discoveredthat lubricating oil compositions particularly useful for heavy dutyservice are obtained by incorporating certain N-polyaminopyrrolidines inoils of lubricating viscosity.

The polyarninopyrrolidines described herein are effective not only asdetergents in lubricating oil compositions, but they also effectivelyneutralize acids which are formed. Thus, by the use of lubricating oilcompositions containing the particular pyrrolidiues described herein,diesel and gasoline engine parts remain remarkably free of deposits andvarnish, even under severe operating conditions.

These polyaminopyrrolidines are 1-aminoalkyl-3-alkenylpyrrolidineswherein the alkenyl radical has at least carbon atoms, more preferablyto 200 carbon atoms, and the alkyl radical has from 2 to 6 carbon atoms.These also include the 1-polyaminoalkyl-3-alkenyl pyrrolidines.

The polyaminopyrrolidines can be represented by the formula:

wherein R is an alkenyl radical having from 30 to about 200 carbonatoms, R is a divalent alkylene radical having from 2 to 6 carbon atoms,and x is a number from dissolved in 9 liters of ethyl ether.

0 to 8. The R radicals may be derived from polyalkylene polyaminereactants.

These pyr-rolidines can be obtained by first preparing thepyrrolidinedione by the reaction of an olefinic hydrocarbon With maleicanhydride. The resulting alkenyl succinic anhydride is then reacted withthe desired polyamine to form the pyrrolidinedione, which then can bereduced (hydrogenated) to form the corresponding pyrrolidine.

Examples of polyalkylene polyamine reactants include diethylenetriamine, dipropylene triamine, tetraethylene pentamine, pentaethylenehexamine, nonaethylenenedecamine, dihexamethylene triamine, etc.

In addition to polyalkylene polyamine reactants, other amines can beused, such as, alkylaminoalkylene amines of the formula:

R2 lEhN-Rl-N wherein R is an alkylene radical, and R and R are alkylradicals having from 1 to 4 carbon times. The sum of carbon atoms in R Rand R is preferably from 3 to 10.

The polyaminopyrrolidines can be prepared by reducing the correspondingalkenyl pyrrolidinedione.

Lubricating oils which can be used as base oils include a wide varietyof lubricating oils, such as naphthenic base, paraffin base, and mixedbase lubricating oils, other hydrocarbon lubricants, e.g., lubricatingoils derived from coal products, and synthetic oils, e.g., alkylonepolymers (such as polymers of propylene, butylene, etc., and themixtures thereof), alkylene oxide-type polymers (e.g., propylene oxidepolymers) and derivatives, including alkylene oxide polymers prepared bypolymerizing the alkylene oxide in the presence of water or alcohols,e.g., ethyl alcohol, dicarboxylic acid esters (such as those which areprepared by esterifying such dicarboxylic acids as adipic acid, azelaicacid suberic acid, sebacic acid, alkanol succinic acid, fumaric acid,maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol,Z-ethyl hexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids ofphosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecylbenzene, tetradecyl benzene, etc., and dialkyl benzenes (e.g., nnonylZ-ethyl hexyl benzene); polyphenyls (e.g. bi phenyls and terphenyls),alkyl biphenyl others, polymers of silicon (e.g., tetraethyl silicate,tetraisopropyl silicates, tetra(4-methyl-2-tetraethyl) silicate, hexyl(4-methyl-2 pentoxy) disiloxane, poly(methyl) siloxane, poly(rnethy1-phenyl) siloxane, etc.

The above base oils may be used individually or in combinations thereof,Wherever miscible or wherever made so by the use of mutual solvents.

These pyrrolidines can be used in oils of lubricating viscosity inamounts of 0.1% to 39% by Weight, preferably 0.25% to 5%, by weight.

The following examples illustrate the preparation of the pyrrolidinesdescribed herein.

EXAMPLE I. PREPARATION OF 1-(TRIETHYL- ENETETRAMINOETHYL) -3OLYTSOBUTENYL PYRROLIDINE Forty-two grams of lithium aluminum hydridewas Twelve hundred grams of approximately 45% petroleum oil solution ofN-tetraethylene pentamine polyisobutenylpyrrolidine-dione, wherein thepolyisobutenyl radical had a molecular weight of about 850 (the oilsolution having a nitrogen content of 1.78%), was added to the ethersolution over a period of 3 hours so as to maintain a gentle reflux.This solution was stirred while refluxing for an additional 6 hours.Thirty milliliters of water was slowly added over a period of 3 hours todecompose unreacted lithium aluminum hydride followed by the addition of470 ml. of water. The mixture was allowed to settle and the ether layerwas decanted and filtered. The ether solution was washed with aqueoussodium carbonate solution, centrifuged, dried over anhydrous sodiumcarbonate, filtered, and freed of solvent under vacuum.

The final product which had a nitrogen content of 1.50% of which 1.13%was basic nitrogen, was essentially free of lithium and aluminum.Infrared analysis showed that the carbonyl groups present in theoriginal pyrrolidinedione were no longer present.

EXAMPLE II.PREPARATION OF l-(TRIETHYL- ENETETRAMINOETHYL) -3POLYISOBUTENYL PYRROLIDINE A six hundred grams of approximately 45%petroleum oil solution of N-tetraethylene pentaminepolyisobutenylpyrrolidinedione, wherein the polyisobutenyl radical had amolecular weight of about 850, was blended with 800 ml. of ethyl ether.This blend was slowly added to a solution of 30 g. of lithium aluminumhydride in 2500 ml. of ethyl ether. The mixture was stirred under refluxfor 12 hours after which 300 ml. of water was slowly added. The ethersolution was washed with aqueous sodium hydroxide and centrifuged. Theether was removed by heating at 150 C. at an absolute pressure of 2 mm.of mercury. Analysis showed a nitrogen content of 1.87% and an absenceof carbonyl groups.

EXAMPLE III.PREPARATION OF I-(B-DIMETH- YLAMINOPROPYL)-3POLYISOBUTENYLPYR- ROLIDINE Seven hundred grams of a 45% petroleum oilsolution of N-dimethylaminopropyl polyisobutenyl pyrrolidinedione, theoil solution having a nitrogen content of 1.04%, was blended with 500ml. of ethyl ether. This solution was slowly added to a solutionconsisting of 20 g. of lithium aluminum hydride in 750 m1. of ethylether. This solution was heated at reflux temperature overnight withagitation. Water was added, the solution filtered, dried over sodiumsulfate, and the solvent removed by distillation to a temperature of 110C. under vacuum. Analysis indicated a nitrogen content of 0.96%, and theabsence of carbonyl groups.

EXAMPLE IV.PREPARATION OF 1-(2-AMINO- ETHY L)-3-POLYISOBUTENYLPYRROLIDINE Two hundred grams of a 34.9% petroleum oilsolution of polyisobutenylsuccinic anhydride having a molecular weightof 1030 was blended with 300 ml. of xylene. This blend was dripped into203 g. of warm, ethylenediamine with agitation. The mixture wasdistilled at 1 atm. to a pot temperature of 150 C. after which a vacuumwas applied to the vessel and the temperature maintained at 170 C. for 2hours.

On analysis, it was found that the nitrogen content was 0.90%, with thebasic nitrogen content being 0.34%. This analysis showed that theproduct was an oil solution containing 34.5% active pyrrolidinedionematerial having a molecular weight of 1072.

The resulting pyrrolidinedione was reduced by slowly adding a solutionconsisting of 100 g. of the pyrrolidinedione dissolved in 100 ml. of dryether to a stirred slurry of 3.5 g. of lithium aluminum hydride in 150ml. of ether. This mixture was refluxed gently for 5 hours, treated withwater, filtered, dried over potassium carbonate and heated to remove thesolvent. On analysis, it was found that the total nitrogen content was0.82%. Infrared analysis showed that no carbonyl groups were present.

EXAMPLE V.-PREPARATION OF l-(6-AMINO- HEXYL) -3-POLYISOBUTENYLPYRROLIDINE The pyrrolidinedione was first prepared byreacting 430 g. of an oil solution (35%) of polyisobutenyl succinic ianhydride (1030 mol wt.) with 350 g. of 1,6-hexanediamine. The solutionwas heated to 170 C. at an absolute pressure of 1 mm. of mercury toremove the excess diamine. The pyrrolidinedione was reduced by dilutingwith ether and dripping the ether solution into a dispersion of 15 g. oflithium aluminum hydride in 500 ml. of ether, followed by treatment inthe manner set forth hereinabove.

On analysis, the product was found to have a total nitrogen content of0.88%.

Table I hereinbelow presents engine data obtained with lubricating oilcompositions containing 7.3% of the oil solution of the pyrrolidine ofExample II hereinabove.

The test was a Caterpillar l-H engine test run for the period of 120hours.

The PD Nos. refer to the piston discoloration rating. After the enginetest, the three piston lands are examined visually. To a piston skirtwhich is completely black is assigned a PD number of 800; to one whichis completely clean, a PD number of 0; to those intermediate betweencompletely black and completely clean are assigned PD numbersintermediate in proportion to the extent and degree of darkening.

The GD Nos. refer to the percentage deposits in the piston ring grooves;a 0 evaluation being a clean groove; and a number of being a groove fullof deposits.

The base oil was a California SAE 30 base oil.

1 These test results were obtained in a Caterpillar L-l test under theMIL-k210i conditions. Thus, under the more severe supplement-1conditions, the GD No. would be considerably higher.

In addition to the pyrrolidines described hereinabove, the lubricatingoil compositions may contain other detergents, rust inhibitors,corrosion inhibitors, pour point depressants, oiliness agents, oxidationinhibitors, etc.

' We claim: 1. A lubricating oil composition comprising a majorproportion of an oil of lubricating viscosity, and from 0.1% to 30% byweight, of l-aminoalkyl-B-alkenyl pyrrolidine wherein the alkenylradical has from 30 to 200 carbon atoms and the alkyl radical has from 2to 6 carbon atoms.

2. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.25% to 5% by weight, of1-aminoalkyl-3-alkeny1 pyrrolidine wherein the alkenyl radical has from30 to 200 carbon atoms and the alkyl radical has from 2 to 6 carbonatoms.

3. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.1% to 30% by weight of anN-aminoalkyl-pyrrolidine of the formula wherein R is an alkenyl radicalhaving from 30 to 200 carbon atoms, R is a divalent alkylene radicalhaving from 2 to 4 carbon atoms, and x is a number from 0 to 6.

4. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.1% to 30% by weight of anN-aminoalkyl-pyrrolidine of the formula R-CHCH3 N-RNR -NH Hg-CH g xwherein R is an alkenyl radical having from 30 to 200 carbon atoms, R isa divalent alkylene radical having 2 carbon atoms, and x is a numberfrom to 6.

5. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.1% to 30% by weight of anN-aminoalkyl-pyrrolidine of the formula R-oH oH,

/N-R-LNR-\NHQ UH -CH, 4 wherein R is an alkenyl radical having from 30to 200 carbon atoms, and R is a divalent radical having 2 carbon atoms.

6. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.25% to 5% by weight of anN-arninoalkyl-pyrrolidine of the formula wherein R is an alkenyl radicalhaving from 30 to 200 carbon atoms, and R is a divalent radical having 2carbon atoms.

7. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity and from 0.1% to 30% by weight of1-(triethylenetetraminoethyl)- wherein R is an alkenyl radical havingfrom to 200 carbon atoms, R is a divalent alkylene radical having from 2to 4 carbon atoms and x is a number from O to 6.

10. As a novel compound, 1-(3-dimethylaminopropyl)-3-polyisobutenylpyrrolidine, wherein said polyisobutenyl radicalcontains from 30 to 200 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 1/62 Anderson etal. 25251.5 3/63 Aspergren 260313 DANIEL E. WYMAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,182,024 May 4, 1965 Frank A. Stuart et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, line 22, for "carbon times" read carbon atoms column 4, lines70 to 75, for that portion of the formula reading column 5, lines 7 to10, for that portion of the formula reading N-R read N-R Signed andsealed this 16th day of November 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OILOF LUBRICATING VISCOSITY, AND FROM 0.1% TO 30% BY WEIGHT, OF1-AMINOALKYL-3-ALKENYL PYRROLIDINE WHEREIN THE ALKENYL RADICAL HAS FROM30 TO 200 CARBON ATOMS AND THE ALKYL RADICAL HAS FROM 2 TO 6 CARBONATOMS.